Convenience stores are packed with products to give consumers a quick boost of caffeine.

The stimulant comes in all forms -- from drinks to pills to sprays -- and is available at almost all locations.

But local health officials told KOCO-TV in Oklahoma City that having too much caffeine can be so serious that it requires a call to a poison-control line or a trip to the emergency room, especially for people younger than the age of 19.

"A typical call is a teen or college student trying to cram for an exam, and they've taken too many tablets to stay awake," said Oklahoma City Poison Control Center manager Lee McGoodwin.

Before the person realizes it, he or she is vomiting and shaking. His or her head is hurting, and his or her heart is beating too fast.

"The number of calls that we've received about energy drinks has tripled, and I think that's just the tip of the iceberg," she said.

In 2006, the Oklahoma City Poison Control Center received 31 calls for caffeine poisoning, five of which were for liquids such as energy drinks. In 2007, those numbers increased in both categories, and 80 calls had been received through nearly 11 months in 2008.

And doctors in Boston found that many calls come from school nurses and parents.

"The concern is once you need two (drinks), you start to need four, and it's really a slippery slope," said Dr. Casey Hester.

The symptoms of caffeine poisoning can also include breathing trouble and diarrhea, according to the National Institutes of Health.

The first step for someone who may have ingested too much caffeine is to stop giving any more. If a trip to an emergency room is required, doctors may use a laxative or stomach pumping to prevent any more stimulant from entering the blood stream.

Keep Kids Away?

Boston pediatrician Dr. John Cohen cautions parents and teenagers to know what they are putting in their bodies, because too much caffeine, he said, could get them into serious medical trouble.

“In my opinion,” Cohen said, “All this stuff should be pulled off the market.”

Drink Makers Respond

The American Beverage Association released a statement saying that its drinks do not pose danger when used correctly.

"Billions of people have enjoyed caffeinated drinks for years. When consumed sensibly, all products can be a part of a healthy lifestyle. These products aren't marketed to kids," it said.

For a list of the caffeine content in some popular drinks, check out this list from "Drug and Alcohol Dependence."

While there is danger, the risk of death may be low. EnergyFiend offers a calculator that tells you how many cans of various drinks it would take to kill a person, based on body weight.

According to the site, for instance, a 160-pound person would need to drink more than 130 cans of Red Bull.